1. Field of the Invention
The invention relates to an image forming apparatus, such as a full-color copying machine, a printer, etc., which forms an image on a recording material by using an electrophotographic method.
2. Related Background Art
In these days, an electrophotographic multicolor or full-color image forming apparatus includes a so-called in-line type image forming apparatus, which is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2001-242680, JP-A No. 2003-202728, and JP-A No. 2004-85899. This in-line type image forming apparatus comprises, as shown in FIGS. 5A and 5B, a plurality of photosensitive drums 100 of respective colors arranged in one line. The image forming apparatus forms color toner images on the photosensitive drums 100, respectively, sequentially superposes the respective formed color toner images onto an intermediate transfer belt 101 to thereby form a color image, secondarily transfers the superposed toner images onto a sheet being conveyed, heat-fixes the superposed toner images to the sheet using a fixing unit, and then discharges the sheet to an output tray 102. According to the above construction, since an exposing unit is disposed at the bottom surface side, it is capable of decreasing a distance at which the toner images are transferred from image forming unit to the intermediate transfer belt 101 and a location at which the color image is transferred from the intermediate transfer belt 101 to the recording material, which effectively shortens a copying time of first sheet.
In such an image forming apparatus, each of the image forming unit 100 and the intermediate transfer belt 101 has a life which is shorter than that of the image forming apparatus main body by its nature; therefore, they need replacement in order to complete the life of the main body. Therefore, as disclosed especially in JP-A No. 2004-85899, an upper cover unit 103 having the output tray 102 and the intermediate transfer belt 101 is, as shown in FIG. 5B, swingably adapted to the image forming apparatus main body in order to make the image forming unit 100 and the intermediate transfer belt 101 replaceable. As a result, swinging the upper cover unit 103 toward above the main body (in the direction of an arrow C in FIG. 5B) enables a user to freely access to both the image forming unit 100 and the intermediate transfer belt 101, which improves the maintainability.
On the contrary, in the above constructed image forming apparatus, in order to easily remove a jammed sheet (clogging sheet) from a sheet convey path, it is considered to rotatably construct a front cover unit 104 as a unit containing the sheet convey path, thereby causing the sheet convey path to be constructed openably.
In this construction mentioned above, because the upper cover unit supports intermediate transfer belt, an opening space formed by the movement of the upper cover unit is necessary to be large. If recording material is stacked on the upper cover unit after fixing process, a distance between the fixing and discharging portion and the upper cover unit is small and they interferes each other when the upper cover unit is opened. On the other hand, if the distance between fixing and discharging portion and the upper cover unit is set large for the upper cover unit can be opened easily, the width of the image forming apparatus becomes large. So it is necessary to reduce the interferance between the upper cover unit at an opening position and the fixing and discharging portion without making the width of the image forming apparatus large.